According to the paper path of a printing system each of the plurality of sheets is transported from an input section of the printing system towards a print head or print assembly. By means of the print head or print assembly marking material is disposed on each of the plurality of sheets. Each of the plurality of sheets is transported from the print head or print assembly towards an output section of the printing system. To enable duplex printing the paper path contains a loop, a so-called duplex loop. A sheet enters the loop in a first pass in order to print image data on one side of the sheet, goes through the duplex loop and enters the duplex loop in a second pass in order to print image data on the other side of the sheet. However, simplex printing—printing on one side of a sheet—may also be executed with a loop in the paper path for interweaving a first and second pass. Such a loop will be called a simplex loop. The present invention relates to a simplex loop as well as to a duplex loop. A print engine with a loop may have a print speed of twice as high as a speed of a separation in the input module and a working speed of an output module or finisher. In such a case the loop may be used to print on the plurality of sheets by interweaving the plurality of sheets in the first pass and in the second pass.
A problem arises when scheduling the plurality of sheets which have different media properties. A media property of a sheet may be a size, a weight, a thickness, a color, a fibre structure, transparency, a media type, etc. The printing system therefore has different timing constraints in the print engine for each kind of sheet having different media properties. Such a timing constraint may be a set up time for a prescribed distance of the print head or print assembly to the sheets which distance may be different for each kind of a sheet. The kind of sheet is determined by the media properties of the sheet.
It is an objective of the present invention to provide a printing system that permits to increase productivity of the printing system with regard to scheduling the plurality of sheets having different media properties.